arXiv subjects

Mikis Mylonakis

Publications and source records attributed to Mikis Mylonakis.

3 recordsLinked to original sources

arXiv2026

Coupling Efficiency and Laser-Induced Damage Threshold Characterization of an End-Capped Optical Fiber with a Sub-Nanosecond Pulsed Laser

This report presents experimental measurements of coupling efficiency and laser-induced damage thresholds for a polarization-maintaining (PM) fiber patchcord with integrated end caps, evaluated at 532 nm using a compact actively Q-switched DPSS laser with sub-nanosecond pulses. It also describes the development of a custom free-space coupling array through which the problem of low coupling efficiency was identified and successfully addressed. No instantaneous damage was observed at peak power densities exceeding 10 GW/cm$^2$. Sustained operation at 30 kHz was maintained over extended durations (>5 h) at peak power densities of ~13 GW/cm$^2$, while prolonged 1 kHz operation led to gradual degradation at peak power densities of ~24 GW/cm$^2$. The broader context of this work is the investigation of stimulated Raman scattering (SRS) in optical fibers for nonlinear frequency conversion. This process requires the efficient delivery of high-peak-power pulses into the fiber, which serves as the nonlinear medium. In the course of these experiments, a substantial dataset was accumulated on fiber coupling performance and damage thresholds under repeated high-intensity illumination at 532 nm. These characterization data offer practical insight into the operational limits of end-capped PM fibers in demanding pulsed laser applications.

physics.optics↗

arXiv2025

Anisotropy enables advanced light sheet microscopy with opaque lenses

Advances in fluorescence microscopy have reached a plateau in improving depth-to-resolution ratios for imaging scattering tissues, highlighting an urgent need for innovative techniques. We introduce Wavelens, a groundbreaking opaque lens that combines dynamic wavefront shaping with a passive, angularly anisotropic photonic scattering plate-designed to scatter light predominantly in one direction. This compact, robust optoelectronic device, comparable in size to a conventional microscope lens, delivers superior light sheet formation capabilities. Using Wavelens, we achieved high-resolution LSFM imaging of diverse biological specimens, including 3D tumor spheroids and the intricate neural architecture of Caenorhabditis elegans in vivo. Notably, Wavelens maintains consistent light sheet properties even in dense, scattering-prone samples, overcoming a long-standing limitation of traditional microscopy. This innovative approach has the potential to revolutionize optical imaging, offering unprecedented clarity and resilience, even within dense, scattering-prone biological samples.

physics.optics↗

arXiv2019

Simple precision measurements of optical beam sizes

We present a simple precision-method to quickly and accurately measure the diameters of Gaussian beams, Airy spots, and central peak of Bessel beams ranging from the sub-millimeter to many centimeters without specialized equipment. Simply moving a wire through the beam and recording the relative losses using an optical power meter, one can easily measure the beam diameters with a precision of 1%. The accuracy of this method has been experimentally verified for Gaussian beams down to the limit of a commercial slit-based beam profiler (3%).

physics.ins-det↗